Kinetic characterization of laccase from Bacillus atrophaeus, and its potential in juice clarification in free and immobilized forms

Lokesh Kumar Narnoliya,Neera Agarwal,Satya N. Patel,Sudhir P. Singh 한국미생물학회 2019 The journal of microbiology Vol.57 No.10

In the present study, a laccase gene (BaLc) from a lignin degrading bacterium, Bacillus atrophaeus, has been cloned and expressed in Escherichia coli. The optimal catalytic activity of the protein was achieved at 5.5 pH and 35°C temperature, measured by oxidation of ABTS. The Km and Vmax values were determined as 1.42 mM and 4.16 μmole/min, respectively. To achieve the enzyme recovery, the biocatalyst (BaLc) was covalently attached onto the functionalized iron magnetic-nanoparticles. The nanoparticles were characterized by zeta-potential and FTIR analyses. The immobilized BaLc enzyme was physico-kinetically characterized, exhibiting retention of 60% of the residual activity after ten reaction cycles of ABTS oxidation. The immobilized biocatalyst system was tested for its biotechnological exploitability in plant juice processing, achieving 41–58% of phenol reduction, 41–58% decolorization, 50–59% turbidity reduction in the extracts of banana pseudo-stem and sweet sorghum stalk, and apple fruit juice. This is the first study to demonstrate the use of nanoparticle- laccase conjugate in juice clarification. The findings suggest that B. atrophaus laccase is a potential catalytic tool for plant juice bioprocessing activities.

Effect of Silencing Groove in Valve Plate on Efficiency of Radial Piston Pump

Lokesh Kumar,Nimai Pada Mandal 한국유체기계학회 2023 International journal of fluid machinery and syste Vol.16 No.2

The recent trend is harvesting more efficient radial piston pumps for industrial applications. The valve plate geometry of the pump plays a crucial role in yielding the pump pressure and flow as a whole generated output power of the pump. The generated output power of the pump is dependent on pump pressure and flow rate, the required input power of the pump is liable to rotational torque and speed. This simulation study designed the valve plate geometry with and without silencing groove and analysed the pump performance, forces, required input mechanical power and generated output fluid power. The silencing groove valve plate plays a vital role in pump performance. The silencing groove is a gradual notch shape volume, contact surface area, and volume slowly increasing toward the manifold. The present study finds out the pump's efficiencies based on output fluid power and inputs mechanical energy for with and without silencing groove model. The simulation results manifest the silencing groove valve plate model is more efficient than the without silencing groove valve plate model of the pump.

Reduced Flow Fluctuation of Radial Piston Pump with Silencing Groove Valve Plate

Lokesh Kumar,Nimai Pada Mandal 한국유체기계학회 2022 International journal of fluid machinery and syste Vol.15 No.1

The theoretical study and numerical analysis have been carried out on the valve plate geometry of the radial piston pump to reduce the flow and pressure fluctuation. The radial piston pump is widely used in industrial applications as a hydraulic power source. The pressure and flow fluctuation of pump produce an adverse effect for the hydraulic system. The geometries of valve plate are studies for the analyses of pressure and flow fluctuation of the pump. The explicit area calculation of the piston kidney over the manifold is carried out to simulate the main flow in between piston chamber and manifold in vale plate configurations of with silencing groove, without silencing groove and with silencing groove cum damping orifice. The analyses of cross-port leakage is done at transition zone near at top dead centre (TDC) and bottom dead centre (BDC) of the valve plate, study the effects of cross-port leakage on pressure and flow fluctuation with volumetric efficiency of the pump. Studies the pump pressure and flow build up characteristic under varying load and validated with existing pump performance. The simulation results suggest that the silencing groove valve plate model is better perform than other configurations in terms of high flow rate, low pressure and flow fluctuation with less cross port leakage and more volumetric efficiency.

Biochemical Performance and Quantitative Assessment of F1 Hybrid of Two Ecoraces of Tropical Tasar Silkworm Antheraea Mylitta Drury (Lepidoptera: Saturniidae)

Lokesh, Gangadharaiah,Tirkey, Sushma Rani,Srivastava, Ashok Kumar,Kar, Prasant Kumar,Sinha, Manoj Kumar Korean Society of Sericultural Science 2013 International Journal of Industrial Entomology Vol.26 No.2

Antheraea mylitta Drury is basically a crossbreeding species, as such it seems to be potentially a good material for the exploitation of heterosis. In the present study F1 hybrid of wild ecorace Laria (L) and semi-domestic Daba (D) was raised and evaluated for various quantitative traits and biochemical parameters during larval stage. Improved fecundity ($+18{\pm}1.8%$ and higher egg hatching rate ($+10.96{\pm}1.3%$) was recorded in the F1hybrid ($L{\times}D$). Biochemical parameters studied in the hemolymph, midgut and fatbody of the larva showed significantly higher (P<0.05) total proteins and carbohydrate concentration besides digestive enzyme activity. Correspondingly SDS-PAGE revealed more number of protein bands in the hemolymph sample of F1s, ranging between 29 kDa to 66 kDa compared to parental lines. The present study demonstrates the positive heterosis effect in the F1 hybrid of Laria ${\times}$ Daba. Biochemical analysis indicates that, there is possibilities of exploitation of hybrids with specific parents targeted for desirable commercial traits (silk yield and fecundity). Moreover, most of these biochemical parameters can be used as markers to analyze the genetic improvement in the tasar silkworms.

The role of diaphragmatic thickness measurement in weaning prediction and its comparison with rapid shallow breathing index: a single-center experience

Lokesh Kumar Lalwani,Manjunath B Govindagoudar,Pawan Kumar Singh,Mukesh Sharma,Dhruva Chaudhry 대한중환자의학회 2022 Acute and Critical Care Vol.37 No.3

Background: Acute respiratory failure (ARF) is commonly managed with invasive mechanical ventilation (IMV). The majority of the time that a patient spends on IMV is in the process of weaning. Prediction of the weaning outcome is of paramount importance, as untimely/delayed extubation is associated with a high risk of mortality. Diaphragmatic ultrasonography is a promising tool in the intensive care unit, and its utility in predicting the success of weaning remains understudied.Methods: In this prospective-observational study, we recruited 54 ARF patients on IMV, along with 50 healthy controls. During a spontaneous breathing trial, all subjects underwent diaphragmatic ultrasonography along with a rapid shallow breathing index (RSBI) assessment.Results: The mean age was 41.8±17.0 and 37.6±10.5 years among the cases and control group, respectively. Demographic variables were broadly similar in the two groups. The most common cause of ARF was obstructive airway disease. The average duration of IMV was 5.41±2.81 days. Out of 54 subjects, 45 were successfully weaned, while nine patients failed weaning. Age, body mass index, and severity of disease were similar in the successful and failed weaning patients. The sensitivity in predicting successful weaning of percent change in diaphragmatic thickness (Δtdi%) >29.71% was high (93.33%), while specificity was 66.67%. The sensitivity and specificity of mean diaphragmatic thickness (tdi) end-expiratory >0.178 cm was 60.00% and 77.78%, respectively. RSBI at 1 minute of <93.75 had an equally high sensitivity (93.33%) but a lower specificity (22.22%). Similar results were also found for RSBI measured at 5 minutes.Conclusions: During the weaning assessment, the purpose is to minimize both premature as well as delayed extubation. We found that diaphragmatic ultrasonography, in particular Δtdi%, is better than RSBI in predicting weaning outcomes.

Biochemical Performance and Quantitative Assessment of F1 Hybrid of Two Ecoraces of Tropical Tasar Silkworm Antheraea Mylitta Drury (Lepidoptera: Saturniidae)

( Gangadharaiah Lokesh ),( Sushma Rani Tirkey ),( Ashok Kumar Srivastava ),( Prasant Kumar Kar ),( Manoj Kumar Sinha ) 한국잠사학회 2013 International Journal of Industrial Entomology Vol.26 No.2

Antheraea mylitta Drury is basically a crossbreeding species, as such it seems to be potentially a good material for the exploitation of heterosis. In the present study F1 hybrid of wild ecorace Laria (L) and semi-domestic Daba (D) was raised and evaluated for various quantitative traits and biochemical parameters during larval stage. Improved fecundity (+18 ± 1.8%) and higher egg hatching rate (+10.96 ± 1.3%) was recorded in the F1hybrid (L x D). Biochemical parameters studied in the hemolymph, midgut and fatbody of the larva showed significantly higher (P<0.05) total proteins and carbohydrate concentration besides digestive enzyme activity. Correspondingly SDS-PAGE revealed more number of protein bands in the hemolymph sample of F1s, ranging between 29 kDa to 66 kDa compared to parental lines. The present study demonstrates the positive heterosis effect in the F1 hybrid of Laria x Daba. Biochemical analysis indicates that, there is possibilities of exploitation of hybrids with specific parents targeted for desirable commercial traits (silk yield and fecundity). Moreover, most of these biochemical parameters can be used as markers to analyze the genetic improvement in the tasar silkworms.

ORiginal Article : Risk Factors for Development of Biliary Stricture in Patients Presenting with Bile Leak after Cholecystectomy

( Hosur Mayanna Lokesh ),( Biju Pottakkat ),( Anand Prakash ),( Rajneesh Kumar Singh ),( Anu Behari ),( Ashok Kumar ),( Vinay Kumar Kapoor ),( Rajan Saxena ) The Editorial Office of Gut and Liver 2013 Gut and Liver Vol.7 No.3

Background/Aims: This study was aimed at determining the factors associated with the development of benign biliary stricture (BBS) in patients who had sustained a bile duct injury (BDI) at cholecystectomy and developed bile leaks. Methods: A retrospective analysis of 214 patients with BDI who were referred to our center between January 1989 and December 2009 was done. Results: One hundred fifty-three (71%) patients developed BBS (group I), and 61 (29%) were normal (group II). By univariate analysis, female gender (p=0.02), open cholecystectomy as the index operation (p=0.0001), delay in the referral from identification of injury (p=0.04), persistence of an external biliary fistula (EBF) beyond 4 weeks (p=0.0001), EBF output >400 mL (p=0.01), presence of jaundice (p=0.0001), raised serum total bilirubin level (p=0.0001), raised serum alkaline phosphatase level (p=0.0001), and complete BDI (p=0.0001) were associated with the development of BBS. Furthermore, open cholecystectomy as the index operation (p=0.04), delayed referral (p=0.02), persistent EBF (p=0.03), and complete BDI (p=0.001) were found to predict patient outcome in the multivariate analysis. Conclusions: For the majority of patients with BDI, the risk of developing BBS could have been predicted at the initial presentation. (Gut Liver 2013; 7:352-356)

Optimization study for enhanced production of hyaluronic acid from Streptococcus equisimilus MK156140

Ashwini Kumar,Savitha Janakiraman,Lokesh Kyathsandra Nataraj 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.9

Hyaluronic acid finds its complete application in areas such as therapeutics, cosmetics, and as a health supplement. In the present investigation, standardization for the production of hyaluronic acid by Streptococcus equisimilus MK156140 in complex media was performed. Some of the selected physicochemical parameters such as pH, temperature, speed, incubation time, sucrose, yeast extract, and beef extract were screened using Plackett-Burman foldover design. Further, the screened parameters interaction was investigated using central composite design (CCD) and closely compared with OVAT studies. At a pH of 7.38, with beef extract, 12.15%, and yeast extract 7.64%, the observed yield was 7.16 g/L, which was in close line with the predicted value of 7.21 g/L.

Duplicated extrahepatic bile duct (type Vb): An important rare anomaly

Vaibhav Kumar Varshney,Sabir Hussain,N. Vignesh,B. Selvakumar,Lokesh Agarwal,Taruna Yadav 한국간담췌외과학회 2023 Annals of hepato-biliary-pancreatic surgery Vol.27 No.2

Original Articvle : Successful Outcome of Refractory Chronic Constipation by Surgical Treatment: A Series of 34 Patients

( Ashok Kumar ),( Hm Lokesh ),( Uday C Ghosha ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2013 Journal of Neurogastroenterology and Motility (JNM Vol.19 No.1

Background/Aims Chronic constipation is commonly managed medically, and surgical options have been advocated in patients with refractory symptoms. We aimed to study the role of surgical procedures in patients with constipation, refractory to medical therapy. Methods Data on 34 surgically managed patients with refractory chronic constipation during a 6-year period (March 2003 to May 2009) were retrospectively analyzed. Results All the 34 patients (24 males and 10 females, median age of 45 years [range, 18-77 years]) had symptoms for a long period (median 96 months [range, 12-360 months]) without response to medical treatment including biofeedback. Preopertive investigations included barium enema, colonoscopy, colonic transit study, defecography and anorectal manometry as indicated. Eight patients (23.5%) had slow transit constipation, 4 (11.8%) had Hirschsprung`s disease and 22 (64.7%) had rectal prolapse. Total colectomy and ileo-rectal anastomosis, anterior resection, Delorme`s procedure, resection rectopexy and Duhamel`s operation were the surgical procedures performed. Though 7 (20.6%) patients had post operative complications, there was no mortality. One patient whose symptoms recurred following anterior resection was successfully treated by total colectomy and ileo-rectal anastomosis. Median spontaneous bowel movements increased following surgical treatment compared to that while on medical treatment (1 per week [range, 0 to 3 per week] vs. 14 per week [range, 7-28 per week], P < 0.00001). Patients remained well during 3-60 months follow-up (n = 27). Conclusions Spontaneous bowel movements significantly increased following surgical operation for refractory chronic constipation, nature of which is dependent on underlying etiology and the expertise available. Careful preoperative work-up and selection of patients are critical for obtaining good functional results. (J Neurogastroenterol Motil 2013; 19:78-84).